Apps for Windows Phone 7 are starting to look pretty healthy now, with some must-have titles hitting the Zune Market. Today Amazon announced that their Kindle ebook reader application will be available for Windows 7 phones later this year (yes, that's being coy about an actual release date). You can sign up for an availability notification with Amazon at www.amazon.com/kindleforwindowsphone .

Features of the free app include:

- Access to over 725,000 books in the U.S. Kindle Store ? the largest selection of the most popular books that people want to read ? including New Releases and 108 of this week?s 111 New York Times Bestsellers.

- With Kindle Worry-Free Archive, books purchased from the Kindle Store are automatically backed up online in a customer?s Kindle library on Amazon, where they can be re-downloaded wirelessly for free, anytime.

- Buy Once, Read Everywhere with the Kindle apps and devices. Amazon's Whispersync technology syncs your place across devices, so you can pick up where you left off.

- Integrated shopping experience that allows customers to shop without leaving the app.

- The opportunity to send an email to a friend with a link to the book you?re reading or to any book in your library without leaving the app.

- Customized reading, choosing from five different font sizes and three background colors.

- The ability to read in portrait or landscape mode, and to turn pages by tapping on either side of the screen or flicking.

- The option to try the beginning of a book for free before buying and to receive personalized recommendations on the home screen of your app.